adults (>18 years) (Boedhoe et al., 2019). We found no shared alterations among all three disorders (even with uncorrected analyses), while shared alterations between any two disorders did not survive correction for multiple comparisons. Children with ADHD compared to those with OCD had smaller hippocampal volumes. Children and adolescents with ADHD also had smaller intracranial volume than control children and those with OCD or ASD. Adults with ASD showed thicker frontal cortices compared to adult controls and other clinical groups. OCD‐specific alterations were not found across different age‐groups and no surface area alterations were found across the disorders. Based on the literature, future cross‐disorder comparisons between OCD and other anxiety disorders, as previously done by Radua et al. (2010), as well as comparison with schizophrenia, which is also characterized by a bigger pallidum (Van Erp et al., 2016) may be useful.
